package com.busfm.util;

/**
 * <p>Title: JNMS(Jutil)</p>
 *
 * <p>Description: �������ϵͳ���������� ά���ˣ��Ͻ���</p>
 *
 * <p>Copyright: Copyright (c) 2008</p>
 *
 * <p>Company: SKYZOO.com.cn</p>
 *
 * @author �Ͻ�
 * @version 1.2
 */


import java.lang.*;
import java.io.*;


public class Base64 {
    private static char[] base64EncodeChars = new char[] {
                                              'A', 'B', 'C', 'D', 'E', 'F', 'G',
                                              'H',
                                              'I', 'J', 'K', 'L', 'M', 'N', 'O',
                                              'P',
                                              'Q', 'R', 'S', 'T', 'U', 'V', 'W',
                                              'X',
                                              'Y', 'Z', 'a', 'b', 'c', 'd', 'e',
                                              'f',
                                              'g', 'h', 'i', 'j', 'k', 'l', 'm',
                                              'n',
                                              'o', 'p', 'q', 'r', 's', 't', 'u',
                                              'v',
                                              'w', 'x', 'y', 'z', '0', '1', '2',
                                              '3',
                                              '4', '5', '6', '7', '8', '9', '+',
                                              '/'};

    private static byte[] base64DecodeChars = new byte[] {
                                              -1, -1, -1, -1, -1, -1, -1, -1,
                                              -1, -1, -1, -1, -1, -1, -1, -1,
                                              -1, -1, -1, -1, -1, -1, -1, -1,
                                              -1, -1, -1, -1, -1, -1, -1, -1,
                                              -1, -1, -1, -1, -1, -1, -1, -1,
                                              -1, -1, -1, 62, -1, -1, -1, 63,
                                              52, 53, 54, 55, 56, 57, 58, 59,
                                              60, 61, -1, -1, -1, -1, -1, -1,
                                              -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
                                              10, 11, 12, 13, 14,
                                              15, 16, 17, 18, 19, 20, 21, 22,
                                              23, 24, 25, -1, -1, -1, -1, -1,
                                              -1, 26, 27, 28, 29, 30, 31, 32,
                                              33, 34, 35, 36, 37, 38, 39, 40,
                                              41, 42, 43, 44, 45, 46, 47, 48,
                                              49, 50, 51, -1, -1, -1, -1, -1};

    private Base64() {}

    public static String encode(String data) {
        return new String(encode(data.getBytes(), data.getBytes().length));
    }

    public static byte[] encode(byte[] data, int len) {
        StringBuffer sb = new StringBuffer();
        int i = 0;
        int b1, b2, b3;

        while (i < len) {
            b1 = data[i++] & 0xff;
            if (i == len) {
                sb.append(base64EncodeChars[b1 >>> 2]);
                sb.append(base64EncodeChars[(b1 & 0x3) << 4]);
                sb.append("==");
                break;
            }
            b2 = data[i++] & 0xff;
            if (i == len) {
                sb.append(base64EncodeChars[b1 >>> 2]);
                sb.append(
                        base64EncodeChars[((b1 & 0x03) << 4) |
                        ((b2 & 0xf0) >>> 4)]);
                sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);
                sb.append("=");
                break;
            }
            b3 = data[i++] & 0xff;
            sb.append(base64EncodeChars[b1 >>> 2]);
            sb.append(
                    base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);
            sb.append(
                    base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]);
            sb.append(base64EncodeChars[b3 & 0x3f]);
        }

        return sb.toString().getBytes();
    }


    public static String decode(String data) {
        return new String(decode(data.getBytes(), data.getBytes().length));
    }

    public static byte[] decode(byte[] data, int len) {

        ByteArrayOutputStream buf = new ByteArrayOutputStream(len);
        int i = 0;
        int b1, b2, b3, b4;

        while (i < len) {

            /* b1 */
            do {
                b1 = base64DecodeChars[data[i++]];
            } while (i < len && b1 == -1);
            if (b1 == -1) {
                break;
            }

            /* b2 */
            do {
                b2 = base64DecodeChars[data[i++]];
            } while (i < len && b2 == -1);
            if (b2 == -1) {
                break;
            }
            buf.write((int) ((b1 << 2) | ((b2 & 0x30) >>> 4)));

            /* b3 */
            do {
                b3 = data[i++];
                if (b3 == 61) {
                    return buf.toByteArray();
                }
                b3 = base64DecodeChars[b3];
            } while (i < len && b3 == -1);
            if (b3 == -1) {
                break;
            }
            buf.write((int) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));

            /* b4 */
            do {
                b4 = data[i++];
                if (b4 == 61) {
                    return buf.toByteArray();
                }
                b4 = base64DecodeChars[b4];
            } while (i < len && b4 == -1);
            if (b4 == -1) {
                break;
            }
            buf.write((int) (((b3 & 0x03) << 6) | b4));
        }
        return buf.toByteArray();
    }
}
